Two fuel carburetor



7 Sheets-Sheet 1 Filed June 19, 1950 INVENTOR. HENRY A. BOLLER BY ATTORNEY S p 1953 H. A. BOLLER TWO FUEL CARBURETOR 7 Sheets-Sheet 2 Filed June 19, 1950 JNVENTOR. HENRY A. BOLLER BY ATTORNEY P 1953 H. A. BOLLER 2,652,237

' TWO FUEL CARBURETOR Filed June 19, 1950 7 Sheets-Sheet 3 INVENTOR. HENRY A. BOLLER ATTORNEY Sept. 15, 1953 H. A. BOLLER 2,652,237

- TWO FUEL CARBURETOR Filed June 19, 1950 7 Sheets-Sheet 4 nnnnnvnnnnn FIG.4.

- INVENTOR. HENRY A. BOLLER ATTORNEY Sept. 1953 H. A. BOLLER TWO FUEL CARBURETOR 7 Sheets-Sheet 5 Filed June 19, 1950 Szo U258 :91

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HENRY A. BOLLER ATTORNEY Illll Sept. 15, 1953 HA. BOLLER 2,652,237 TWO FUEL CARBURETOR Filed June 19, 1950 7 Sheets-Sheet e INVENTOR. HENRY A. BOLLER vATTORNEY Sept. 15, 1953 H. A. BOLLER 7 2,652,237 TWO FUEL CARBURETOR Filed June 19, 1950 '7 Sheets-Sheet 7 MIDDLE OF BLEND Illa JNVENTOR. FIG. l0. HENRY A. BOLLER ATTORNEY Patented Sept. 15, 1953 2,652,237 TWO FUEL CARBURETOR Henry A. Boller, Pontia corporation of Delaware 0, Mich., assignor to Carter Carburetor Corporation, St. Louis, Mo., 21.

Application June 19, 1950, Serial No. 168,978

20 Claims.

particularly in a novel means for improving the efficiency of engines by supplying fuels of different anti-knock qualities, according to the power demand on the engine, and means whereby the transition from low octane to high octane operacreases with more expensive fuels having higher anti-knock qualities. ever, during normal operation of a vehicle under low speed light load conditions, since relatively low compressions exist in the cylinders, less expensive fuels of lower anti-knock, or octane ratings will suflice. Since the octane ratings of various inexpensive low octane fuels are likely to vary considerably, the degree of throttle opening and/or the compression at which detonation is likely to occur will vary accordingly.

An object of this invention is, therefore, to produce a carburetor a low octane fuel mixture for idling and for low speed light load operation but which will permit until manifold vacuum reaches a predetermined low value, at which point the transfer to high octane fuel is always made.

Another object is to provide a carburetor of this type in which the speed range during which place may be varied by changing metering pins. As an example, utilizing one given set of metering pins will provide a blending 40 and 45 miles per hour, part throttle; whereas, by substituting a different set mile per hour speed difierential to miles per hour speed diiferential, as from 40 to 60 miles per hour.

which will always provide A further object is to provide a carburetor of this type in which the transition from low to high octane fuel or vice versa is accomplished so smoothly as to be unnoticeable.

A still further object is to provide a carburetor of this type in which the idle system, operated from the low octane fuel supply, may be rendered completely inoperative when the degree of throttle opening exceeds a small predetermined. value, in order to prevent dilution of the high octane fuel, and to prevent alteration of the air-fuel ratio.

Additional objects and advantages will appear from the specification and the drawings, in which:

Fig. 1 is a vertical sectional view of a buretor made according to this invention;

Fig. 2 is an elevation of one side of the carburetor of Fig. 1, partially sectionalized;

Fig. 3 is an elevation of the opposite side of the same carburetor, partially sectionalized;

Fig. 4 is a plan view of the carburetor, parts being sectioned;

Fig. 5 is a diagram showing the relative positions of the low octane and high octane metering pins during various throttle positions;

Fig. 6 shows the metering pin control mechanism in the part throttle, low octane position;

Fig. 7 shows the metering pin control mechanism in the part throttle, high octane position;

Fig. 8 shows the metering pin control mechaoctane position;

Fig. 9 shows a sectional View of mechanism for advancing the metering pins to part throttle 10W octane position;

Fig. 10 shows a modified pins.

Referring now to the drawings, the numeral H3 refers to a carburetor having an air horn ii, dual mixture conduits I2 formed with stacked venturis l3 therein, low octane fuel chamber l4 and high octane fuel chamber l5. A flange i6 is carform of the metering formed at the outlet end of mixture conduits (2 for attachment to the manifold of an internal combustion engine. Admission of air to the mixture conduits is automatically controlled by disk choke valve I! mounted on shaft I8. Conventional throttle valves l9, mounted on shaft 2i, control the outlets of mixture conduits [2.

Fuel is admitted to fuel chambers I 4 and I5 and kept at constant level therein by float controlled needle valves 23 and 24, respectively, the outlet of fuel from the fuel chambers being through two calibrated low octane metering orifices 25 and two high octane orifices 2B. Passageways 2i and 28 provide fuel connections between orifices Z5 and 26 and fuel nozzles 29 and Sil which discharge into the mixture conduits i2 through the uppermost venturis i3.

Passage of fuel through orifices and it is regulated by metering pins 8! and 32, the characteristics and operation of which. will be described in detail below. Fuel for idling passes directly, and not through orifices 25, from low octane fuel chamber i4 into and through conventional restricted idle tubes (not shown), through passages 33 and into mixture conduits l2 through idle ports it and idle adjustment ports t ll.

Referring now to Fig. 2, it will additional fuel increments for acceleration are provided by an accelerating pump 35 of conventional piston type construction which forms a part of the wall structure of high octane fuel chamber and receives its fuel therefrom through inlet check valve 3? and passageway 33. Fassageway 39, from pump 3% to pump nozzles id (shown in Fig. 1) and, in part, passing through ribs lied and dill) and including an outlet check permits supply of accelerating charges from pump it into mixture conduits i2. Coil spring s! mounted in the pump cylinder, normally urges plunger d2 upwardly, to eliminate slack in the pump linkage. Discharge movements of pump plunger 42 are effected by loosely pivoted rocker which is operatively connected by shaft l8, tight lever i'l', tension spring ilot, and link to throttle lever it, rigidly mounted at one end of throttle shaft 2i.

Throttle operating lever 4% is in the form of a bell chank having at one end an opening it to receive the accelerator pedal connecting rod, and at the other a journal $9 to receive fast idle connecting link 5%. For varying the minimum, normal idle opening of the throttle, a conventional adjustment screw 5,! is provided on lever Adjacent journal .9, a compressible spring loaded 52 is connected at one end to lever and at the other end to crank 53 which is secured to an end of shaft lit. Shaft 54 is rotatably journalled in bracket 55 and is provided with downwardly extending flaps 55 which are adapted to actuate combination shut-off and air bleed valves in the idle systems. The combination shut-off and air bleed valves, comprising housings 58 formed connected air passages 6d, and spring actuated closure members iii slidably mounted therein, communicate with the idle systems adjacent idle ports springs 62 normally urge stems 53 of closure members ti outwardly to close air bleed passages Throttle actuated fiaps 56 are so positioned with respect to the outer end of plungers 63 that when throttle valves it are opened to a predetermined position fiaps 56 urge stems t3 inwardly, thereby opening air passages t0 into communication with idle passages 33 and causing closure members M to close idle ports 34. Thus, at a predetermined throttle opening, air is bled into the idle system, and idle ports 35 are closed, thus rendering When this occurs, since the maximum permissible movement of flaps lit is considerably less than that of throttle lever 66, compressible linl;

d2 compresses to absorb additional throttle move- I 4 inent.

Referring now to Fig. 5, which utilizes one low octane and one high octane metering pin to show certain relative positions of the low and high octane metering pins in their simultaneous upward and downward movements, it will with atmospheric ports 53%),

the idle system inoperative. 6

be noted that low octane metering pin 3| is of substantially equal diameter with low octane metering orifice 25, and has formed in its cylindrical face an elongated relatively deep recessed flat em. Flat Sic is formed with upper and lower edges substantially normal to the axis of metering pin 3%, and is so spaced with referonce to metering orifice 25 that when the throttles are tightly closed the entire fiat is below the metering orifice, thus permitting the cylindrical portion of the metering pin 3! to sealingly close the orifice.

High octane metering pin 32 is also of substantially equal diameter with its orifice 26 and is formed with a stepped recessed flat 32a having its upper edge at an intermediate level with respect to the upper and lower edges of flat am of low octane metering pin 3!. The lower portion of stepped fiat 32a is substantially deeper than the upper portion and extends to the lower end of high octane metering pin 32.

Movement of metering pins ti and E2 is as shown in Fig. 5, and is controlled in a manner which will be described in detail below. When the throttles are tightly closed, both low octane high octane metering pins 3i and 32 close their respective metering orifices 25 and 28, as shown at A. During idling, both metering pins are simultaneously elevated a slight distance, but still close their respective orifices, as shown at vlfnen the throttles are somewhat farther opened, the metering pins are raised an additional distance so that flat film is substantially bisected by metering orifice 25 as at C, permitting a maximum flow of low octane fuel therethrough; at this point high octane metering pin continues to close its orifice if it is desired that low octane fuel be used throughout the operating range, the carburetor be, as explained hereafter, so adjusted that, as the throttle opening increases, there will be no further elevation of metering pins 3! and 32 after they have reached the part throttle low octane position shown at C, in Fig. 5. They will remain at position C until manifold vacuum declines to a predetermined value, in the order of 5 inches Hg; thereupon the pins are raised to the full power, or step-up position shown at F, in Fig. 5, with low octane metering orifice 25 closed and the deep portion of fiat 32a in the high octane metering orifice 25, thus permitting a maximum flow of high octane fuel only to the engine.

If, on the other hand, it is desired that a transfer from low octane to high octane fuel be made at any desired throttle opening, the carburetor may be so adjusted that when the throttle reaches the desired opening the metering pins will resume their simultaneous upward movement, as shown at D, until the lower edge of flat 3la is just below low octane metering orifice 25, thus permitting only a very slight fiow of fuel therethrough, and the upper edge of notch 32a is just above the high octane metering orifice 26, thus permitting slight passage of high octane fuel therethrough; during this range blending and changeover from low to high octane operation takes place. During remaining throttle opening movement, the metering pins continue their simultaneous upward movement, so that the low octane metering pin completely closes its orifice 25 and the upper relatively shallow portion of flat 32a. is in the high octane orifice as at E, Fig. 5, thus permitting the passage therethrough of the maximum quantity of high octane fuel desirable for part throttle operation. When manifold vacuum decreases to a predetermined low value, low octane metering pins 3| continue to close their orifice as at F, and the deeper flattened portion of high octane metering pins 32 pass into orifices 26', thereby permitting a passage therethrough of the full power requirement of high octane fuel.

Referring now to 3, a fuel selector lever 64 is rotatably journalled on the carburetor body in line with the throttle shaft. At its end adjacent the low octane fuel chamber, a link 65 connects fuel selector lever 64 to a crank 66 which is rigidly mounted on an end of countershaft El which in turn is rotatably journalled in posts 68 above the fuel bowl cover. At its other ends, crankiifi is connected to spring loaded plunger 69, in dashpot 10 which communicates with 10w octane fuel chamber 14, below the fuel level therein, so that any movements of plunger 69 are resisted by the necessity of displacing fuel in the dashpot. Thus, counterclockwise movements of fuel selector lever 64 are dampened by the retarding effect of upward movement of plunger 69, whereas clockwise movements are not substantially retarded, being facilitated by compression of the plunger spring.

Rigidly secured to countershaft 61 is metering pin arm H (shown in Fig. 1), to the outer ends of which are secured the eye portions of low octane metering pins 3i so that movements of metering pins 3| correspond to those of fuel selector lever 64. Conventional metering pin springs normally urge the unflatted sides of metering pins 3| into sealing engagement with metering orifices 25. A second arm '52 formed with outwardly extending lips 73 is clamped to countershaft Gl. Lips 73 are adapted to abut against the upper surface of springloaded plungers '14 (shown in detail in Fig. 9), which are normally urged upwardly a limited distance by spring 75. The adjustment of lips 13 is such that when plungers M are depressed the metering pins are positioned as at A in Fig. 5, and as plungers 14 move upwardly toward their uppermost position, they urge arm 12, countershaft El, and metering pin arm H counterclockwise, thereby elevating the metering pins to position C of Fig. 5 in which the maximum of low octane fuel is supplied.

A link '76 is journalled at its lower end in the high octane end of fuel selector lever 64 and at its upper end in crank ll. Crank l? is mounted on an end of countershaft l8, and is provided with an inwardly directed nearly radial lip 19 on its outer end portion. Another crank 80 is rotatably journalled on the end of countershaft 18 between crank Ti and journal post 8|. Crank 80 is of generally rectangular form except for an outwardly extending projection 82 from the upper portion of its free end. A, torsion spring 83 normally urges projection 82 into abutting relation with the upper surface of lip l9 until crank 80 is rotated so far that its lower corner engages the bowl cover 84, which prevents crank 80 from following crank Tl any further. The purpose of this device is to limit the throttle produced, upward movement of the metering pins, as will be described hereafter, to the medium, high octane position shown at E in Fig. 5, yet topermit further movement of crank ll and the metering pins to the full power, high octane position shown at F. The unflatted sides of metering pins 32 are urged into engagement with metering orifices 26 by a conventional metering pin spring mounted on arm 85.

For varying response of the metering pins and,

thus, the transfer from low to high octane operation with respect to throttle opening, the following mechanism is provided: adjacent the low octane end of fuel selector lever 64, a generally triangular member 86 and an adjustment finger Bl are rotatably mounted on a common pivot 88 on the fuel selector lever. A set screw 89, passing through an arcuate slot 90 in member 86 and into lever 64, serves to hold member 86 in any desired relation to fuel selector lever 64. Adjustment finger 8'! is of relatively long, narrow shape, being pointed at its free end; a coil spring 9|, secured at its lower end to finger 8'! and at its upper to the upper apex of member B6, urges finger 87 into abutting engagement with a turned out lip portion 92 formed adjacent the lower free apex of member 86. Adjacent the free, pointed end of finger 81, a calibrated scale 93 is marked on fuel selector lever 64. Adjustment of finger 8'! with respect to scale 93 is accomplished by moving member 86 until the pointer is set at the desired calibration 93, and then tightening set screw 89.

For transmitting throttle movement to fuel selector lever 64, and through it to the metering pins, a disk 95, provided with outwardly extending pin 96, is rigidly mounted on throttle shaft 21, adjacent fuel selector lever 64, so that pin 96 projects through an arcuate slot 98 in the selector lever. The greater weight of the low octane end of selector lever 64 and spring 52 (Fig. 2) normally urge selector lever 64 in a counterclockwise direction. When the throttles are fully closed, pin 96 bears against the upper end of slot 98, thereby preventing any clockwise movement of selector lever 64; at this position of selector lever 64 the metering pins are bottomed in their receiving pockets, as at A, Fig. 5. As the throttle is opened to the idle position, pin 96 moves a slight distance clockwise, thus permitting selector lever G l, urged by spring plungers 14, as described above, to move a slight distance clockwise; this movement elevates metering pins 3| and 32 to the idle position, as shown at B, Fig. 5. The maximum movement of the metering pins under the influence of spring plungers 24 is illustrated at C in Fig. 5.

When adjustment finger B1 is set at the lowest calibration (Fig 8), the only movement of selector lever 64 occurs during initial throttle opening movement which moves pin 96 clockwise thus permitting clockwise movement of selector lever 64 and elevation of metering pins 3| and. 32 to the part throttle, low octane position shown at C, Fig. 5. When the adjustment finger is set thus, further opening movement of throttles I9 has no direct effect on selector lever 64, so that during the entire operating range, except when manifold vacuum is very low, as will be described hereafter, the metering pairs remain stationary and the carburetor will continue to provide a low octane part throttle fuel mixture, as at C, Fig. 5. Preferably, the metering pin position C supplies an economy or low power fuel-air mixture.

Referring now to Figs. 6 and 7, as the setting of adjustment finger 8'! is changed upwardly with respect to calibrated scale 53, obviously throttle pin 96 will engage finger 81 at relatively smaller throttle openings, thus causing greater response of the fuel selector lever 64 and the metering pins to full throttle movement. Position D represents the middle of the transfer range between the low and high octane fuels and position E represents the highest position to which the throttles can elevate the pins.

provide These positions are reached at progressively smaller throttle openings as finger 81 is moved upwardly and the degree of throttle opening at which this throttle actuated advance is initiated, can be varied throughout the operating or part throttle range.

In view of the above, it will be readily understood that by adjusting finger 81 at the uppermost calibration on scale 93, the carburetor will a high-octane fuel mixture only throughout practically the entire operating range. On the other hand, when finger 81 is set at the lowermost calibration, the carburetor will provide low octane fuel only throughout the entire operating range, except when manifold vacuum declines below a predetermined low value. By setting finger 61 at intermediate calibrations the changeover from low to high octane operation can be accomplished at any point between these two extremes where it is determined the anti-detonant property of the high octane fuel is required. Regardless of the setting of finger 81, throttle movements cannot move the metering pins past position E, of Fig. 5, at which position the fuel selector mechanism ceases further movement when lever Bil is stopped by the bowl cover.

This cessation of movement occurs because coil spring 9! is weaker than torsion spring 83, so that when lever 80 is stopped by contact with the bowl cover 84, throttle pin 96 will merely urge finger B1 downwardly, stretching coil spring 9!, but not causing any further movement of fuel selector lever 64. When this occurs, the high test metering pins are at position E, of Fig. 5, with the shallow upper portion of flat 32a in the metering orifice.

Changes in manifold vacuum are transmitted from mixture conduit l2 posterior to throttles l9 (Fig. 3) via a port 98a, duct 99 and 100, and tubular passage NJ! to suction chamber H32, where, at a predetermined low vacuum diaphragm I03 and its plunger R36 are urged rightwardly by spring I05. Diaphragm spring W5, is stronger than torsion spring 83, so that when manifold vacuum in suction chamber I02 becomes very low, spring W5 urges plunger Hi6 against a lip H38 on fuel selector plate 64, thereby urging plate 64 clockwise, link 16 downward, and lever 11 clockwise until lip 19 is stopped by the bowl cover 84 (Fig 8), thus elevating the metering pins to their extreme upward position F, with the deep portion of flat 32a located in high octane metering orifice 26, thereby permitting a maximum fiow of fuel therethrough. Metering pin position F can be reached only when the throttles are fully open, but this position is independent of the position of adjust ment finger 81. 7

Referring now to Figs. 3, 6, '7 and 8, operation of the device at an intermediate setting can be seen. In Fig. 3, the throttles H! are opened slightly beyond their idling positions and pin 96 thus rotated a short distance from its closed throttle position. Thereupon spring loaded plungers 14 act through arm 12, ccuntershaft 61 and lever 64 to raise the metering pins to position C, of Fig. 5. In Fig. 6, throttles l9 have continued their opening movement and throttle pin 96 has moved a similar distance clockwise, but has not yet acted against adjustment finger 8'5, there intermediately positioned, so that fuel selector lever 64 and metering pins 3! and 32 are still in the part throttle low octane position of Fig. 5.

throttle opening movement has continued, thus causing pin 96 to urge intermediately located finger 81 downwardly. Downward movement of finger 81 is transmitted through spring BI and member 86 to fuel selector arm 64, causing a clockwise movement thereof. This latter movement is transmitted to metering pins 3| and 32, ultimately causing them to move from position C through position D to position E of Fig. 5 with the throttles nearly fully open. Thus the transfer was made from low octane to high octane operation. At this point, crank Bil engages the bowl cover 84, and, through torsion spring 83 resists further clockwise movement of crank l! and fuel selector lever 64. As throttle opening continues, and as throttle pin 96 moves clockwise additional distances, its movement is transmitted to finger 81, but not to fuel selector lever 64, since coil spring 9|, not being sufficiently strong to overcome the resistance of torsion spring 83, stretches.

Regardless of additional throttle opening movement, fuel selector plate 64 and the metering pins SI and 32 remain as shown in Fig. '1 until manifold vacuum decreases to a predetermined low value, in the order of 5 inches Hq.

Referring now to Fig. 8, when such a reduction in vacuum occurs, and as long as it exists, provided the throttles are wide open, the diaphragm coil spring I05 urges plunger we outwardly into abutting engagement with lip I98 on fuel selector lever 64. Since coil spring I05 is stronger than torsion spring 83 which thus far has resisted further rotation of crank l1 and of fuel selector lever 64, plunger Hi6 urges fuel selector lever 64 and crank ll clockwise in opposition to spring 83 until lip is on crank 11 engage the bowl cover, as in Fig. 8. When this occurs, the metering pins 3i and 32 are in their full power, high octane positions, as at F, Fig. 5, so that a maximum flow of high octane fuel is permitted.

As manifold vacuum increases, or as the throttles are moved toward their closed position, the same sequence is repeated in reverse, the rate of transition from high to low octane fuel being slightly retarded by the necessarily relatively slow upward movement of dashpot plunger as. It should be noted, in this regard, that downward movement of dashpot plunger 69, being absorbed by its spring, offers almost no resistance to elevation of the metering pins during throttle opening movements.

Referring now to Fig. 10, it will be noted that a modified form of the low and high octane metering pins is shown in a position similar to C of Fig. 5. Modified low octane metering pin III is identical with metering pin 3|, except that the lower edge of its flat I I la, instead of being horizontal, is slightly bevelled. High octane metering pin I I2 is identical with metering pin 32, except that the upper edge of its flat 2a is also slightly bevelled. Obviously this bevelling permits a longer simultaneous opening of the two metering orifices, and thus a more gradual blending of the low and high octane fuels. Thus, the speed range during which blending of the two fuels takes place can be increased, for example from 5 miles per hour, using metering pins 3| and 32 to 20 miles per hour, using the modified me- In Fig. 7,

tering pins l l i and I I2, the increase in the blending range depending, of course, on the angle and depth of the bevel.

The invention disclosed herein may be modified in various respects as will occur to those skilled in the art, and the exclusive use of all 9 such modifications as come within the scope of the appended. claims is contemplated.

I claim:

1. In an internal combustion engine having an intake conduit, a throttle valve therein, a pair of fuel chambers adapted, respectively, for storing low and high octane fuel, a fuel supply passage leading from each of said chambers to said conduit, valves controlling said passages, spring actuated throttle responsive means for opening said low octane valve to its maximum opening, throttle actuated means for closing said low octane valve and opening said high octane valve a predetermined amount, said throttle actuated means being adjustable for actuation at any desired throttle opening, and means responsive to suction in the intake conduit for advancing said high octane metering pin to its maximum opening.

2. In an internal combustion engine having an intake conduit, a throttle valve therein, a pair of fuel chambers adapted, respectively, for storing low and high octane fuel, fuel supply passages leading from each of said chambers to said conduit, valves controlling said passages, spring actuated throttle responsive means for opening said low octane valve to its maximum opening, throttle actuated means for simultaneously closing said low octane valve and opening said high octane valve a predetermined amount, said throttle actuated means being adjustable for actuation at any desired throttle opening, means responsive to suction in the intake conduit for advancing said high octane metering pin to its maximum opening, additional fuel passage means including a restricted portion leading directly from said low octane fuel chamber to said intake conduit adjacent the throttle valves to provide fuel for idling, and additional throttle responsive means for rendering inoperative said additional fuel passage means at a predetermined small throttle opening.

3. In an internal combustion engine having an intake conduit, a throttle valve therein, a pair of fuel chambers adapted respectively for storing low and high octane fuel, fuel supply passages leading from each of said chambers to said conduit, a calibrated metering orifice in each of said passages, metering pins slidably mounted in said metering orifices, said metering pins being adapted to sealingly close said orifices and being formed with elongated recessed portions to permit passage of fuel when said portions are in registry with said orifices, said recessed portion of said low octane metering pin being normally in close proximity with said low said recessed portion of said high octane metering pin being in relatively less proximity with its orifice, spring actuated throttle responsive means for moving said recessed portions toward said orifices until the recessed portion of said low octane pin is substantially bisected by its orifice, permitting a maximum flow of low octane fuel therethrough, and throttle actuated means for moving said pins until part of the recessed portion of each is in its metering orifice thereby permitting a blend of fuels and for further moving said metering pins until said low octane orifice is sealingly closed and said high octane orifice is opened a predetermined amount, said throttle actuated means being adjustable for actuation at any desired throttle opening.

4. In an internal combustion engine having an intake conduit, a throttle valve therein, a pair of fuel chambers adapted respectively for storing low and high octane fuel, fuel supply passages octane orifice,

10 leading from each of said chambers to said conduit, a calibrated metering orifice in each of said in relatively less proximity with its orifice, spring actuated throttle responsive means for moving said reduced portions toward said orifices until octane pin is submaximum flow throttle actuated means for until part of the reduced portion of each is in its metering orifice thereby permitting a blend of fuels, said throttle actuated means further movuntil said low octane orirequirement of high octane fuel to pass therethrough.

5. In an internal combustion engine having an intake conduit, a throttle valve therein, a pair of fuel chambers adapted respectively for storin each of said passages, metering pins slidably mounted in said metering orifices for simultaneous movetowards and through said metering orifices to effectuate, successively, opening of said low oc- 6. In an internal combustion engine having an intake conduit, a throttle valve therein, a pair of fuel chambers adapted respectively for storing low and high octane fuel, fuel supply passages leading from each of said chambers to said conduit, a calibrated metering orifice in each of said for simultaneous movement, said metering pins being adapted to sealingly and being formed with elongated reduced portions to permit passage of fuel orifice to permit leading from each of said chambers 11 duced portions toward said orifices until the re-' duced portion of said low octane pin is substantially bisected by its orifice, permitting a maximum flow of W octane fuel therethrough, and throttle actuated means for simultaneously moving said pins until part of the reduced portion of each is in its metering orifice thereby permitting a blend of fuels and for further moving said metering pins until said 10w octane orifice is sealingly closed and said first step of said high octane metering pin is in said orifice to permit the maximum part throttle requirement of high octane fuel to flow therethrough, said throttle actuated means being adjustable for actuation at any desired throttle opening.

7 7. In an internal combustion engine having an intake conduit, a throttle valve therein, a pair of fuel chambers adapted respectively for storing low and high octane fuel, fuel supply passages leading from each of said chambers to said conduit, a calibrated metering orifice in each of said passages, metering pins slidably mounted in said metering orifices for simultaneous movement, said metering pins being adapted to sealingly close said orifices, said metering pins being formed with elongated reduced portions to permit passage of fuel when said reduced portions are in registry with said orifices, said reduced portion of said low octane metering pin being normally in close proximity with said low octane orifice, said reduced portion of said high octane metering pin being in relatively less proximity with its orifice and being formed in two steps, the step farthest from the orifice being .the deeper, spring actuated throttle responsive means for moving said reduced portions toward said orifices until the reduced portion of said 10W octane pin is substantially bisected by its orifice, permitting a maximum flow of low octane fuel therethrough, throttle actuated means for simultaneously moving said pins until part of the reduced portion of each is in its meterin orifice thereby permitting a blend of fuels and for further moving said metering pins until said low octane orifice is sealingly closed and said first step of said high octane metering pin is in said the maximum part throttle requirement of high octane fuel to fiow therethrough, said throttle actuated means being adjustable for actuation at any desired throttle opening, and means responsive to suction posterior to the throttle for moving said metering pins until said deeper step of said high octane metering pin is in its orifice, thus permitting a maximum fiow of high octane fuel therethrough.

' 8. In an internal combustion engine having an intake conduit, a throttle valve therein, a pair of fuel chambers adapted, respectively, for storing and high octane fuel, fuel supply passages to said conduit, valves controlling said passages, spring actuated throttle responsive means for opening said low octane valve to its maximum opening, throttle actuated means for simultaneously closing said low octane valve and opening said high octane valve a predetermined amount, said throttle actuated means being adjustable for actuation at any desired throttle opening, additionalfuel passage means including a restricted portion leading low directly from said low octane fuel chamber to said intake conduits adjacent the throttle valves to provide fuel for idling, and additional throttle responsive means for rendering inoperative said additional fuel passage means at a predetermined small throttle opening,

. take manifold for 12 said additional throttle responsive means coniprising a throttle actuated combination cut-off and air bleed valve.

9. In an internal combustion engine having an intake conduit, a pair of fuel chambers adapted respectively for storing low and high octane fuel, fuel passage means leading from each of said fuel chambers to said intake conduit, a calibrated metering orifice in each of said fuel passages, a metering pin normally sealingly closing each of said orifices, each of said pins having a reduced portion, and means responsive to throttle move-. ment and to vacuum in the intake manifold for moving said metering pins in unison, said reduced portion on the lowoctane metering pin being adapted for positioning in the metering orifice during light load operation at low speeds, the reduced portions of said low octane and high octane pins being adapted for positioning in their respective orifices simultaneously to effect a blend of fuels and transfer from low to high octane operation, the reduced portion of said high octane metering pin being adapted for positioning in its orifice during the remainder of the operating range.

10. In an internal combustion engine having an intake conduit, a pair of fuel chambers adapted respectively for storing low and high octane fuel, fuel passage means leading from each of said fuel chambers to said intake conduit, a calibrated meteringorifice in each of said fuel passages, a metering pin normally sealingly closing each of orifices, each of said metering pins havinga reduced portion, means responsive to throttle movement and to vacuum in the inmoving said metering pins in unison, said reduced portion on the low octane metering pin being adapted for positioning in the metering'orifice during light load operation at low speeds, the reduced portions of said low octane and high octane pins being adapted for positioning in their respective orifices simultaneously to effect a blend of fuels and transfer from low to high octane operation, the reduced portion of said high octane metering pin being adapted for positioning in its orifice during the remainder of the operatin range, and manually adjustable means for determining at what throttle opening the metering piIlS shall advance.

"11. In an internal combustion engine having a plurality of intalze conduits, a pair of fuel chambers adapted respectively for storing low and high octane fuel, fuel passage means leading from each of said fuel chambers to said intake conduits, a'calibrated metering orifice in each of said fuel passages, a metering pin normally sealingly closing each of said orifices, a fiatted portion on each of said metering rods, means responsive to throttle movement and to vacuum in the intake manifold for moving said metering pinsin unison, said fiatted portion on the low octane metering being adapted for positioning in the metering orifice during light load operation at low speeds, the fiatted portions of said low octane and high octane pins being adapted for positioning in their respective orifices simultaneously to effect a blend of fuels and transfer from low to high octane operation, the fiatted portion of said high octane metering pin being adapted for positioning in its orifice during the remainder of the operating range, manually adustable means for determining at what throttle Y opening the metering pins shall advance, an, in-

dependent idle system comprising passages lead-,- ing from said low octane fuel chamber to said intake conduits and including a throttle actulost motion part, and a second, more resistant, ated combination air bleed and shut-oil valve for yielding part, said first yielding part being adrendering said idle system inoperative at a prejustable to vary th pick-up between said throttle determined small throttle opening prior to transand said operative connection means during fer from low to high octane operation.

12. In an internal combustion engine having ing shifting of said control valves by said throttle, a plurality of intake conduits, a pair of fuel said first yielding part yielding to permit conchambers adapted respectively for storing low tinued throttle opening movement thereafter, and

from each of said fuel chambers to said intake for causing further shifting of said control valve said fuel passages, a metering pin normally sealing to permit such second mentioned further ingly closin each of said orifices, a iiatted pormovement of said control valves. tion on each of said metering rods, means re- 16. A carburetor as described in claim in sponsive to throttle movement and to vacuum 111 15 which said suction responsive device operates on ation at low speeds, the flatted portions of said tle valve therein, a pair of fuel chambers, respecfor positioning in their respective orifices simulsupply passage leading from each chamber into taneously to effect a blend of fuels and transfer said conduit, a control valve in each passage, a from low to high octane operation, the fiatted lever loosely pivoted adjacent and axially with portion of said high octane metering pin being relation to said throttle valve, an element movadapted for positioning in its orifice during the able with said throttle valve, a second lever pivremainder of the operating range, said high oted to said first lever and normally positioned octane metering pin fiatted portion being formed to be engaged by said throttle element to transto low vacuum in the intake conduits for posisecond lever being adjustably mounted for vary- 13. In a carburetor, a mixture conduit, a shifting of the same upon movement of said first said conduit, a control valve for each passage, including a device responsive to mixture conmeans operatively connecting said throttle and duit suction having a one-Way connection with said valves, said means including a yielding part said first lever for shifting the same so as to and being normally shiftable as a unit to dlfactuate said valve when the conduit suction drops ferentially actuate said valves upon opening of excessively. v said throttle, a stop normally cooperating with A a u etor a pecified n claim 17 in said part to limit movement of said valv s, a d which said second lever is resiliently mounted on means responsive to suction in said conduit for said first lever and further including a resilient yielding to permit such additional v l movedirection the resilient mounting of said second ment lever yielding upon engagement of said stop to 14. In a carburetor, a mixture conduit, a throtpermit further t tt openin movement.

tle therein, a, pair of fuel chambers, a, fuel supply 20. A carburetor as specified in claim 17 further passage leading from each chamber into said conincluding a yielding element earned y sald pduit, a control valve for each passage, means operatlve 00111160151011, a p eab by said elea second, more resistant yielding part, a stop nor- Suction in said mixture conduit for additionally mally limiting shifting of said valves to predeshifting Said valves a a n t sa d stops.

termined positions, said first part yielding to per- HENRY O ER- mit continued throttle opening movement thereafter, and a device responsive to mixture con- References clted m the file of thls patent duit suction for causing further shifting of said UNITED STATES PATENTS valves beyond said predetermined position, said second part yielding to permit such last mengi g a} Jul z tioned further movement of said valves. 1841046 Mortenson 5" g 1932 15. In a carburetor, a mixture conduit, a 1944063 Corse 1934 throttle therein, a pair of fuel chambers, a fuel 2142979 Hans 1939 Supply Passage leading from each chamber into zjzsojeoe Crawford Oct. 28 1941 said conduit, a control valve for each passage, 2,297,109 Moseley Sept 1942 means operatively connecting said throttle and 2,444,179 Anderson June 1 said valves, a lost motion part, a first yielding P part constituting one of the elements of said 

